From 6069fcc1a22b340c5071f72e7dc3ff93b309639f Mon Sep 17 00:00:00 2001
From: Kittywhiskers Van Gogh <63189531+kittywhiskers@users.noreply.github.com>
Date: Tue, 12 Oct 2021 12:46:07 +0530
Subject: [PATCH] merge bitcoin#14667: Add deriveaddresses RPC util method

---
 src/rpc/client.cpp                     |  2 +
 src/rpc/misc.cpp                       | 91 ++++++++++++++++++++++++++
 test/functional/rpc_deriveaddresses.py | 50 ++++++++++++++
 test/functional/test_runner.py         |  2 +
 4 files changed, 145 insertions(+)
 create mode 100755 test/functional/rpc_deriveaddresses.py

diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index ac6272d5fef6c..af5bea8beeac6 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -83,6 +83,8 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "sendmany", 6, "use_is" },
     { "sendmany", 7, "use_cj" },
     { "sendmany", 8, "conf_target" },
+    { "deriveaddresses", 1, "begin" },
+    { "deriveaddresses", 2, "end" },
     { "scantxoutset", 1, "scanobjects" },
     { "addmultisigaddress", 0, "nrequired" },
     { "addmultisigaddress", 1, "keys" },
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index 9a4f9a2021ead..71e51c08b2370 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -17,6 +17,7 @@
 #include <rpc/blockchain.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
+#include <script/descriptor.h>
 #include <timedata.h>
 #include <txmempool.h>
 #include <util/system.h>
@@ -291,6 +292,95 @@ static UniValue createmultisig(const JSONRPCRequest& request)
     return result;
 }
 
+UniValue deriveaddresses(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.empty() || request.params.size() > 3) {
+        throw std::runtime_error(
+            RPCHelpMan{"deriveaddresses",
+            "\nDerives one or more addresses corresponding to an output descriptor.\n"
+            "Examples of output descriptors are:\n"
+            "    pkh(<pubkey>)                        P2PKH outputs for the given pubkey\n"
+            "    sh(multi(<n>,<pubkey>,<pubkey>,...)) P2SH-multisig outputs for the given threshold and pubkeys\n"
+            "    raw(<hex script>)                    Outputs whose scriptPubKey equals the specified hex scripts\n"
+            "\nIn the above, <pubkey> either refers to a fixed public key in hexadecimal notation, or to an xpub/xprv optionally followed by one\n"
+            "or more path elements separated by \"/\", where \"h\" represents a hardened child key.\n"
+            "For more information on output descriptors, see the documentation in the doc/descriptors.md file.\n",
+                {
+                    {"descriptor", RPCArg::Type::STR, /* opt */ false, /* default_val */ "", "The descriptor"},
+                    {"begin", RPCArg::Type::NUM, /* opt */ true, /* default_val */ "", "If a ranged descriptor is used, this specifies the beginning of the range to import"},
+                    {"end", RPCArg::Type::NUM, /* opt */ true, /* default_val */ "", "If a ranged descriptor is used, this specifies the end of the range to import"}}
+                }.ToString() +
+            "\nResult:\n"
+            "\"address\"        (array) A json array of the derived addresses\n"
+            "     [\n"
+            "       ...\n"
+            "     ]\n"
+            "\nExamples:\n"
+            "\nFirst three receive addresses\n"
+            + HelpExampleCli("deriveaddresses", "\"pkh([d34db33f/84h/0h/0h]xpub6DJ2dNUysrn5Vt36jH2KLBT2i1auw1tTSSomg8PhqNiUtx8QX2SvC9nrHu81fT41fvDUnhMjEzQgXnQjKEu3oaqMSzhSrHMxyyoEAmUHQbY/0/*)\" 0 2")
+        );
+    }
+
+    RPCTypeCheck(request.params, {UniValue::VSTR, UniValue::VNUM, UniValue::VNUM});
+    const std::string desc_str = request.params[0].get_str();
+
+    int range_begin = 0;
+    int range_end = 0;
+
+    if (request.params.size() >= 2) {
+        if (request.params.size() == 2) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Missing range end parameter");
+        }
+        range_begin = request.params[1].get_int();
+        range_end = request.params[2].get_int();
+        if (range_begin < 0) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Range should be greater or equal than 0");
+        }
+        if (range_begin > range_end) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Range end should be equal to or greater than begin");
+        }
+    }
+
+    FlatSigningProvider provider;
+    auto desc = Parse(desc_str, provider);
+    if (!desc) {
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Invalid descriptor"));
+    }
+
+    if (!desc->IsRange() && request.params.size() > 1) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range should not be specified for an un-ranged descriptor");
+    }
+
+    if (desc->IsRange() && request.params.size() == 1) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range must be specified for a ranged descriptor");
+    }
+
+    UniValue addresses(UniValue::VARR);
+
+    for (int i = range_begin; i <= range_end; ++i) {
+        std::vector<CScript> scripts;
+        if (!desc->Expand(i, provider, scripts, provider)) {
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Cannot derive script without private keys"));
+        }
+
+        for (const CScript &script : scripts) {
+            CTxDestination dest;
+            if (!ExtractDestination(script, dest)) {
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Descriptor does not have a corresponding address"));
+            }
+
+            addresses.push_back(EncodeDestination(dest));
+        }
+    }
+
+    // This should not be possible, but an assert seems overkill:
+    if (addresses.empty()) {
+        throw JSONRPCError(RPC_MISC_ERROR, "Unexpected empty result");
+    }
+
+    return addresses;
+}
+
 static UniValue verifymessage(const JSONRPCRequest& request)
 {
     if (request.fHelp || request.params.size() != 3)
@@ -1139,6 +1229,7 @@ static const CRPCCommand commands[] =
     { "control",            "logging",                &logging,                {"include", "exclude"}},
     { "util",               "validateaddress",        &validateaddress,        {"address"} },
     { "util",               "createmultisig",         &createmultisig,         {"nrequired","keys"} },
+    { "util",               "deriveaddresses",        &deriveaddresses,        {"descriptor", "begin", "end"} },
     { "util",               "verifymessage",          &verifymessage,          {"address","signature","message"} },
     { "util",               "signmessagewithprivkey", &signmessagewithprivkey, {"privkey","message"} },
     { "blockchain",         "getspentinfo",           &getspentinfo,           {"json"} },
diff --git a/test/functional/rpc_deriveaddresses.py b/test/functional/rpc_deriveaddresses.py
new file mode 100755
index 0000000000000..6170780a996d8
--- /dev/null
+++ b/test/functional/rpc_deriveaddresses.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+# Copyright (c) 2018 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test the deriveaddresses rpc call."""
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, assert_raises_rpc_error
+
+class DeriveaddressesTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.supports_cli = 1
+
+    def run_test(self):
+        assert_raises_rpc_error(-5, "Invalid descriptor", self.nodes[0].deriveaddresses, "a")
+
+        descriptor = "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/0)"
+        address = "yZTyMdEJjZWJi6CwY6g3WurLESH3UsWrrM"
+
+        assert_equal(self.nodes[0].deriveaddresses(descriptor), [address])
+
+        descriptor_pubkey = "pkh(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/0)"
+        address = "yZTyMdEJjZWJi6CwY6g3WurLESH3UsWrrM"
+
+        assert_equal(self.nodes[0].deriveaddresses(descriptor_pubkey), [address])
+
+        ranged_descriptor = "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/*)"
+        assert_equal(self.nodes[0].deriveaddresses(ranged_descriptor, 0, 2), [address, "ydccVGNV2EcEouAxbbgdu8pi8gkdaqkiav", "yMENst4XYP3ZSNvsCEm587GbSSXZUfhpWG"])
+
+        assert_raises_rpc_error(-8, "Range should not be specified for an un-ranged descriptor", self.nodes[0].deriveaddresses, "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/0)", 0, 2)
+
+        assert_raises_rpc_error(-8, "Range must be specified for a ranged descriptor", self.nodes[0].deriveaddresses, "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/*)")
+
+        assert_raises_rpc_error(-8, "Missing range end parameter", self.nodes[0].deriveaddresses, "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/*)", 0)
+
+        assert_raises_rpc_error(-8, "Range end should be equal to or greater than begin", self.nodes[0].deriveaddresses, "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/*)", 2, 0)
+
+        assert_raises_rpc_error(-8, "Range should be greater or equal than 0", self.nodes[0].deriveaddresses, "pkh(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/*)", -1, 0)
+
+        combo_descriptor = "combo(tprv8ZgxMBicQKsPd7Uf69XL1XwhmjHopUGep8GuEiJDZmbQz6o58LninorQAfcKZWARbtRtfnLcJ5MQ2AtHcQJCCRUcMRvmDUjyEmNUWwx8UbK/1/1/0)"
+        assert_equal(self.nodes[0].deriveaddresses(combo_descriptor), ["yZTyMdEJjZWJi6CwY6g3WurLESH3UsWrrM", "yZTyMdEJjZWJi6CwY6g3WurLESH3UsWrrM", "93EpXofs6W7eNiuj4gu2LJh8L8opowW1jz"])
+
+        hardened_without_privkey_descriptor = "pkh(tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1'/1/0)"
+        assert_raises_rpc_error(-5, "Cannot derive script without private keys", self.nodes[0].deriveaddresses, hardened_without_privkey_descriptor)
+
+        bare_multisig_descriptor = "multi(1, tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/0, tpubD6NzVbkrYhZ4WaWSyoBvQwbpLkojyoTZPRsgXELWz3Popb3qkjcJyJUGLnL4qHHoQvao8ESaAstxYSnhyswJ76uZPStJRJCTKvosUCJZL5B/1/1/1)"
+        assert_raises_rpc_error(-5, "Descriptor does not have a corresponding address", self.nodes[0].deriveaddresses, bare_multisig_descriptor)
+
+if __name__ == '__main__':
+    DeriveaddressesTest().main()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index 30399e5a1db5d..417a5aef84ee6 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -211,6 +211,8 @@
     'p2p_blockfilters.py',
     'feature_asmap.py',
     'feature_includeconf.py',
+    'rpc_deriveaddresses.py',
+    'rpc_deriveaddresses.py --usecli',
     'rpc_scantxoutset.py',
     'feature_logging.py',
     'p2p_node_network_limited.py',